Marine growth, in particular hard-fouling organisms such as barnacles, oysters and tubeworms together with soft-fouling organisms such as anemones and hydroid sponges, have long been recognised as a major cause of problems which affect the integrity of structures submerged in seawater in a number of ways:
Such marine growth adds detrimental extra mass to a submerged structure. PA0 It increases the roughness of exposed surfaces, thus increasing the hydro-dynamic loading, on a structure. PA0 It enlarges the dimensions of underwater members such as legs, underpinnings, struts, etc., and hence the surface areas of structures subjected to fluid loading. PA0 It obscures underwater surfaces, thus preventing necessary visual surveillance.
Periodical removal of such marine fouling by careening and scraping has been employed as a principal means of controlling marine growth fouling on offshore oil platforms for decades. Traditionally, copper-plating and, later, Muntz metal-plating were used on ships' hulls and, recently, marine growth inhibition has again been realised by the introduction of anti-fouling paints and other anti-fouling materials such as plates or panels of cupro-nickel tightly fitted to cleaned members. These methods, however, have become prohibitively expensive both because of the time-consuming and costly diving operations involved and because of the anti-fouling materials used.